The Handheld Digital Multimeter  DMM 10

After working for several years as an Electronics Technician prior to graduating as a Radio Engineer, I realised that the portable test equipment used by Technicians had several shortcomings. They were hard to handle , inaccurate , heavy , hard to read , fragile and poorly protected from physical shock.

This AVO portable analog multimeter ( the Industry Standard ) weighed 4.5 kg including carry-case and had an accuracy of 2% FSD as well as a hard to interpret logarithmic Ohms scale.  At the time, Digital Voltmeters were large mains powered bench or rack mounted instruments about the size of a Hi Fi amplifier and, needing mains power, they were not suitable for portable use.

There was an urgent need for a new approach to portable instruments!
The ideal solution was an accurate , small , light weight , robust ,  easily read , well protected Digital Multimeter, so in 1976 I decided to set about designing one from scratch. New LED Display chips had become available and a new series of CMOS logic chips were announced. After 9 months of after-hours work in my shed at home I had finally created a prototype which accurately displayed voltage on an angled 3 digit LED display. The next task was to design a second circuit which enabled the meter to measure DC/AC Volts, Amps and Ohms with three selectable ranges of X1, X10 , X100 , this took a further 3 months.
Since I did not have a manufacturing capability I decided to approach local manufacturers and ARLEC was the obvious choice. They had manufacturing facilities in Melbourne and Hong Kong as well as an injection moulded plastic housing which could easily be adapted to house the Multimeter. They were impressed with the concept and agreed to enter into a Licensing Agreement to Manufacture and Market the Handheld Digital Multimeter in Australia with the model number  DMM10.

The DMM10 was released for sale in November 1977 and was displayed on the Cover of The Electronics Australia magazine in the March 1978 Edition complete with a feature article “The A&R story” written by Leo Simpson. Recently it has been claimed that in 1977 Clive Sinclair (U.K) and Fluke (U.S.) were developing similar digital meters simultaneously with the DMM10 following the release of a newly available A-D chip.